The present invention relates to a printing system, print request terminal, compression algorithm selecting program and printing method for transferring and printing compressed print data between the print request terminal and a printer.
Various efforts have been made to reduce printing time, and increasing the speed of data transfer is one technique. In order to increase the speed of data transfer, a print data compressing method has been conventionally used. By compressing print data, an amount of transfer data is reduced so that the data transfer time can be reduced. The information processor disclosed in JP-A-2003-29938 is, for example, a technology relating thereto.
According to the invention disclosed in JP-A-2003-29938, in order to print compressed image data by JPEG (Joint Photographic coding Experts Group), for example, based on a scaling rate of a compressed image to be printed, processing power of a host computer and/or printer and a data transfer rate therebetween, a total processing time for creating and printing an uncompressed print image in the host computer side and a total processing time required for extending and printing in the printer side are estimated and compared. Based on the comparison result, the one requiring a shorter processing time is selected, and printing processing is performed thereon.
However, since an optimum method is determined in accordance with processing power of an entire system and/or a data transfer rate according to the invention disclosed in JP-A-2003-29938, the determination takes time though it is effective for the reduction of a print execution time (time from the receipt of print data by a printer to the completion of the printing) and the data transfer time. Therefore, in consideration of the time up to the determination time, the printing time (time from a print request by a user to the completion of the printing) may be larger than that of a case without the compressing method disclosed in JP-A-2003-29938 as a result, which is a problem.
The compression of print data is generally performed not only by the invention disclosed in JP-A-2003-29938 but also generally by a fixed compression algorithm. This is because dynamically (adaptively) determining an optimum compression algorithm requires time for calculation and may increase the printing time as a result.
However, since a compression algorithm's compression efficiency largely depends on the type of print data, sufficient compression efficiency cannot be achieved with a fixed compression algorithm, which is another problem. For example, when print data mainly includes images, a compression algorithm tailored to the compression of image data may be used. When print data mainly includes text, a compression algorithm tailored to the compression of text data may be used.
Accordingly, the invention was made in view of the unsolved problems of the conventional technologies. It is an object of the invention to provide a printer system, print request terminal, compression algorithm selecting program and printing method suitable for reducing printing time.